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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Posted on 15 January 2018 by John Abraham

The refugee crisis – particularly in the Mediterranean area – has received large amounts of new attention in the past few years, with people fleeing from Syria and entering the European Union emblematic of the problem. There has been some research connecting this refugee problem with changes to the climate. In particular, the years preceding the Syrian refugee crisis were characterized by a severe drought that reduced farm output and led to economic and social strife there.

Separating out the influences of climate change from general social instability may be impossible, because they are intimately linked. But we do know that climate change can cause social and economic instability. We also know that these instabilities can boil over into larger problems that lead to mass exodus. The problem isn’t knowing the connection between climate and refugees exists – rather the problem is quantifying it.

All of this is important because we want to be able to plan for the “now” as well as the “tomorrow.” If we are already seeing climate-related migrations, can you imagine what’s in store in the next few decades as temperatures and extreme weather continue to increase?

The researchers identified 103 countries that contributed to asylum applications to the European Union. Collectively, these nations submitted 350,000 applications to the EU per year. The authors combed the weather histories from these 103 source sites and explored how the weather varied in the 2000–2014 time period.

They found that when temperatures in agricultural areas and seasons at the source countries varied away from an optimal value (of about 20°C), the number of people seeking asylum increased. And the increase wasn’t just proportional. They found it was nonlinear, meaning that initial increases in temperature only mildly changed the asylum application numbers. But as temperatures varied more and more, the number of seekers increased more quickly.

After making this connection to observations, the authors then projected into the future. Using a collection of climate models that are able to predict Earth’s future climate, the authors estimated that on a business-as-usual emissions pathway (where countries don’t meaningfully reduce greenhouse gas emissions), asylum applications will increase by almost 200% by the end of the century. On the other hand, under a modest warming scenario, where humans take some meaningful action to reduce emissions, the increase falls to about 30%. Again, this shows that what humans do today to combat climate change really matters.

What was also interesting is that temperature is a better metric for this problem than precipitation. I wouldn’t have guessed that initially; my naïve expectation would be that precipitation changes would also be very good at allowing prediction of asylum seekers. But it turns out temperature is much better. The discussion by the authors also demonstrated how many moving parts there are to this problem. Not only are the economic, climate, and social situations in the source country important, but those factors in the destination country are also critical. People migrate to where they expect better conditions.

I spoke with the authors who told me this about their choice of using temperature as the metric for asylum applications:

There is an emerging literature linking various sectoral outcomes in a country to weather shocks (conflict, agricultural yields, energy demand, mortality, labor productivity, labor supply, etc.). Using temperature shocks is ideal from a statistical perspective; our statistical model is not new, but well established.

With much study on the topic in recent years, I wanted to know what contribution this new paper had made (that wasn’t known already). They said this:

Comments

The article talks about impacts of high temperatures on agriculture. I wonder if people are also just tired of the extreme heat. Syria average summer temperature is 30 degrees. It could be part of the reason for the migration.

“While it is record-breaking that tends to make news, scientists say it is the unbroken run of hot days in the high 30s and 40s that causes the significant problems for human health, and other life.”It’s not being able to cool down at night, and in the days that follow, that causes problems,” he says. (Death rates spike during heatwaves)

“I was camping in the Blue Mountains [west of Sydney] on Saturday night. It was about 30 degrees at midnight, and I could feel my heart racing. Now, that extra stress on my cardiovascular system didn’t kill me, but it might have if I was 20 years older.”

Good points, nigel, especially about night time temperatures, and we all know that GW effects those most strongly. I also wonder if in some places the humidity levels are also exacerbating the problems with mere livability.

It must be difficult to separate the influence of climate change from the influence of the destabilization of Eastern countries by incessant wars, more often than not caused by America. For instance, how do you evaluate the situation in Yemin with regard to refugees. America is fighting a proxi war there, using the Saudis. It is a very hot dry region but how has the exodus of refugees changed since the beginning of that war. The war in Iraq led to the formation of ISIS as the Americans in their wisdom forbade anyone who had been a baathist from participating in the government. Since even to be a dog catcher, you had to belong to the party, this eliminated anyone of tallent and sent them into the arms of radicalism. How do you separate climate change refugees from war refugees. Incidentally, the so called Conservation Agriculture (see Montgomery, Growing a Revolution) would go a long way to mitigating the effects of greater floods and stronger droughts as it stores water in the soil when it is available for use during the dry.